In Pixar's Cars, former Piston Cup champion Doc Hudson becomes the judge of Lightning McQueen's road-repair sentence.
Doc is the respected physician and judge of Radiator Springs. After McQueen damages the town's main road, Doc orders him to repair it before leaving. McQueen initially sees the task as an unfair delay, but the work brings him into closer contact with the town and begins his personal transformation.
Doc's hidden history is that he was the Fabulous Hudson Hornet, a three-time Piston Cup champion who raced in the early 1950s. A crash ended his competitive career, and he became bitter after the racing world moved on without him. McQueen's arrival gives Doc a chance to mentor another racer.
The King is a different veteran champion, while Sheriff enforces local law rather than serving as the judge. Doc's connection to McQueen's sentence is one of the film's key reveals.